ctms.to_vendor() could not convert unknown data

[robhudson]

After the is_waitlist changes, we're seeing some sentry errors for unknown data for "fpn_country".

https://mozilla.sentry.io/issues/4087704376/?project=6260602&query=is%3Aunresolved&referrer=issue-stream&stream_index=0

[leplatrem]

The following data is posted:

email: [Filtered]
format: H
fpn_country: br
lang: en
newsletters: guardian-vpn-waitlist
source_url: https://www.mozilla.org/en-US/products/vpn/invite/

When the slug guardian-vpn is sent, we should consume fpn_* fields.

Same as relay-vpn-bundle and relay-phone-masking slugs, which should consume relay_* fields.

The piece of code responsible of "converting" data is this one:

basket/basket/news/backends/ctms.py

Lines 236 to 248 in cdab6d1

	# Specific cases for legacy waitlists:
	new_fields = {
	"relay_country": "relay_geo",
	"fpn_country": "vpn_geo",
	"fpn_platform": "vpn_platform",
	}
	# Turn flat fields into a dict.
	fields = {}
	for name, raw_value in data.items():
	if name in new_fields:
	consumed_key = name
	name = new_fields[name]

This is a bug, and I don't find appropriate tests in test_ctms.py. We can fix this. Please assign the issue to me.

[robhudson]

We deployed the change and are still seeing these warnings come through in Sentry.